MOSS IN THE LAWN

Is moss taking over your lawn? Spring is an excellent time to eradicate it.

Moss is generally caused by compacted soil, sour soil, overwet soil, too
much shade or improper fertilization. Through a process of elimination you
can determine which of these conditions is responsible, so it can be corrected.
It is important to understand that until the cause is eliminated, moss will
continue to grow in the affected area.

The first job is to kill the moss. There are several chemical moss-killers
available at local garden outlets. Ferrous ammonium sulfate is the material
most-often contained in such products and it will turn moss black in a short
period of time. Once it has turned black, rake it out of the grass. Should
bare spots remain, prepare the soil and reseed the affected areas.

Lawn moss control products are available under many different brand names.
Some of the spring fertilizers also contain a moss killer, so you can accomplish
two jobs at the same time if you have not already fertilized. This may be
the easiest and most economical way to remove the moss. Follow application
directions on the label of the product you use.

Once the moss has been eliminated, it is time to correct the soil condition
that caused it to flourish. As I have already mentioned, it will return until
the cause is removed.

The best way to find out what is causing the moss to grow is to cut a 4"
X 4" plug of grass from the affected area for observation. Examine the grass
plants and the soil in which they are growing. Here is what you should look
for:

If the problem is compacted, sour or poorly-drained soil, it is a good idea
to perforate the lawn area with an aerating machine, a manure fork, pitchfork
or spading fork. This will allow for better air circulation and will permit
water and nutrients to get down into the soil where they can do some good.
If possible, perforate to a depth of at least three to six inches. The holes
should be about four to six inches apart. If the area is shady or if you
have not fertilized properly in the past, you still may find it necessary
to perforate the lawn.

Sour Soil - Sour odor. A soil test
will verify this. Contact your local County Extension Service for details.

If you determine that the soil is sour, calcium should be applied to the
lawn area as an additional corrective measure. It is a soil sweetener and
can be applied after the grass has been fed. Dolomite lime is often recommended
for this job. It should be applied at the rate of 40 pounds per 1,000 square
feet. This product will also add magnesium carbonate to the soil, an element
often lacking in the lawns of this area. One application will probably not
be sufficient to correct the soil condition; in fact, a second application
in the fall and a third the following spring may be required. Spreader settings
generally appear on the bag.

Over-wet Soil - Compacted soil that water cannot penetrate. Sour soil
can be detected. Low spots in the lawn can also be the cause.

If the cause of the moss is overwet soil and compacted soil is not the problem,
drainage should be improved by filling in the low spots, then reseeding.
Perforating will help improve drainage if compacted soil is the problem as
discussed above.

Too Much Shade - Wrong type of grass seed used.

When moss is caused by too much shade, one solution may be to eliminate the
grass in that area. Ornamental flower and shrub beds can be created and
shade-loving plants added. Where removing the grass is impractical or
undesirable, shade type grass can be used. Such products are sold under that
title or may be referred to as fescue mixtures.

Improper Fertilization - Limited root growth; sickly green color.

If improper fertilization is the cause of the problem, start a regular feeding
program at once. The grass needs to be fed in spring, summer and fall with
a well-balanced fertilizer. Avoid brands that have a high nitrogen content;
they tend to stimulate top growth only.

If high nitrogen fertilizers are used, they should have a calcium base and
should only supplement the use of well-balanced types. If you have a moss
problem and use ammonium sulfate as a supplement during the summer months
to improve color, substitute calcium nitrate instead. The calcium will be
beneficial in sweetening the soil. However, high nitrogen fertilizers do
not provide all the nutrients the lawn requires to maintain good health and
vigor.

Once you have solved the cause of the moss in your lawn, the grass should
be much easier to maintain. Arrange a regular schedule for mowing and be
sure the mower is set at the correct height. Most Northwest lawns contain
bent and fescue grasses and should be cut at the 3/4 inch height; bluegrass
lawns should be cut at 1 1/2 inches.

Be sure to provide sufficient water during the dry season and undertake insect
or disease control if either becomes necessary. But, by all means eliminate
any moss that may be growing and correct the cause. It will then be much
easier to keep the lawn looking nice throughout the entire year.